You keep your socks on so that's not really an issue. I personally don't let anyone wear shoes in our house, I don't know what they've stepped on so I don't want them dragging anything over the floors and carpets.
Socks doesn't fix the problem completely. Unfortunately, visitors don't like being told that they can keep the socks on while walking on the carpet, but if they are to sit on the bed or put the feet up on the couch, they should take it off.
Don't even feel like discussing how clean are fresh are everyone's socks.
I wouldn't tell them to ever take their socks off, the only rule in our house is no shoes in the house.
Agree socks might not be 100% clean but you have to draw the line somewhere, and the bottom of a sock is bound to be cleaner than the bottom of a shoe.
In central Europe it's common to have a special room called checkroom/garderobe next to your main door where you store several pairs of guest slippers.
Don't even feel like discussing how clean are fresh are everyone's socks.